John Hayes (dates unknown) was a British merchant captain and maritime explorer active in the late 18th and early 19th centuries. He is primarily remembered for his voyage to Australia in 1793, during which he explored and named the Derwent River in Van Diemen's Land (modern-day Tasmania).
Hayes sailed from Bengal in India aboard the ships Duke of Clarence and Duchess with the intent of establishing trade and potentially a British settlement in the region. He entered the Derwent River in April 1793 and spent several weeks exploring its shores, charting its features, and making contact with the indigenous Aboriginal population.
He claimed the territory for Great Britain and named the river the Derwent, after the Derwent River in his native Cumberland, England. He also named several other geographic features, including Risdon Cove (after his second officer William Risdon) and Clarence Plains (after the Duke of Clarence, later King William IV).
Hayes' exploration predated the official British settlement of Van Diemen's Land under Lieutenant John Bowen in 1803. His detailed charts and reports provided valuable information for future explorers and settlers. However, his claim of possession was largely disregarded by the British authorities, who established their settlement further up the river at what is now Hobart.
Little is known about Hayes' life beyond this voyage. His contributions to the early exploration and mapping of Tasmania are acknowledged, though his role is often overshadowed by the later establishment of the colony. He remains a significant figure in the maritime history of Australia.